REVELATIONS that Education Secretary Ruth Kelly approved a registered sex offender to work with children has shocked teachers' unions.

It was reported at the weekend that, acting on the advice of civil servants, the minister - MP for Bolton West - allowed a man, who police believe had looked at child-porn websites, to work as a PE teacher.

He was only stopped when police protested. Mick Brookes, general secretary of the National Association of Head Teachers, said the case highlighted the need to make further changes to the education employment system.

He said: "There have been massive strides to encourage agencies to work together in recent years, but this case demonstrates a need to make sure all parties - including politicians and political groups - work together with agencies on a regional and national level."

'Caution'

Mr Brooke urged caution when dealing with such a case and said: "We need to be very careful because I know of a case where nothing was proven. We must be cautious when making judgements until we know all the facts."

The decision to allow the man to take the job at a high school in Norfolk was taken after Ms Kelly apparently believed that evidence that he had accessed paedophile websites was inconclusive.

Ms Kelly is understood to believe her decision was correct, which is likely to further alarm experts who say that politicians should not decide on who is prevented - or not - from working with children.

A Norfolk police said: "Swift action was taken as soon as this matter came to our attention."